Question

You may need to use the appropriate appendix table or technology to answer this question. Software companies work hard to produce software that does not have bugs in it. The average number of bugs found in a new software program at its inception is 26.5 with a standard deviation of 3.5 bugs. A random sample of size 45 software programs was examined. (a) Determine the mean (in bugs) of the sampling distribution of the sample mean for samples of size 45. .58 bugs (b) Calculate the standard deviation (in bugs) of the sampling distribution of the sample mean of samples of size 45. (Round your answer to three decimal places.) bugs (c) The shape of the sampling distribution of the sample mean is approximately normal. Which of the following choices justifies that statement? We have sampled less than 10% of the population. A random sample was taken. Tchebysheff's Theorem tells us that the distribution is approximately normal. The sampling distribution of the sample mean is always normally distributed. The population is approximately normally distributed. The sample size is 30 or more, so the Central Limit Theorem tells us that the distribution is approximately normal. (d) What is the probability that in a random sample of size 45 software programs, the company would find an average of 27 or more bugs? (Round your answer to four decimal places.)

Answer #1

You may need to use the appropriate appendix table or technology
to answer this question.
Barron's reported that the average number of weeks an
individual is unemployed is 18.5 weeks. Assume that for the
population of all unemployed individuals the population mean length
of unemployment is 18.5 weeks and that the population standard
deviation is 4 weeks. Suppose you would like to select a sample of
60 unemployed individuals for a follow-up study.
(a) Show the sampling distribution of x,...

You may need to use the appropriate appendix table or technology
to answer this question.
A simple random sample with
n = 59
provided a sample mean of 26.5 and a sample standard deviation
of 4.4. (Round your answers to one decimal place.)
(a)
Develop a 90% confidence interval for the population mean.
to
(b)
Develop a 95% confidence interval for the population mean.
to
(c)
Develop a 99% confidence interval for the population mean.
to
(d)
What happens to...

You may need to use the appropriate appendix table or technology
to answer this question. A production process is checked
periodically by a quality control inspector. The inspector selects
simple random samples of 40 finished products and computes the
sample mean product weights x. If test results over a long period
of time show that 5% of the x values are over 2.1 pounds and 5% are
under 1.9 pounds, what are the mean and the standard deviation (in
lb)...

You may need to use the appropriate appendix table or technology
to answer this question. A population has a mean of 200 and a
standard deviation of 50. Suppose a sample of size 100 is selected
and x is used to estimate μ. (Round your answers to four decimal
places.)
(a) What is the probability that the sample mean will be within
±5 of the population mean?
(b) What is the probability that the sample mean will be within
±10...

You may need to use the appropriate appendix table or technology
to answer this question. The following random sample from a
population whose values were normally distributed was collected. 11
11 17 17 What is the 80% confidence interval for μ?
A. 10.000 to 18.000
B. 10.536 to 17.464
C. 11.163 to 16.837
D. 12.542 to 15.458

You may need to use the appropriate appendix table or technology
to answer this question.
A newspaper reports that the average expenditure on Valentine's
Day is $100.89. Do male and female consumers differ in the amounts
they spend? The average expenditure in a sample survey of 40 male
consumers was $137.67, and the average expenditure in a sample
survey of 30 female consumers was $65.64. Based on past surveys,
the standard deviation for male consumers is assumed to be $45,...

You may need to use the appropriate appendix table or technology
to answer this question.
Consider the following hypothesis test.
H0: μ ≥ 10
Ha: μ < 10
The sample size is 130 and the population standard deviation is
assumed known with σ = 5.Use α = 0.05.
(a) If the population mean is 9, what is the probability that
the sample mean leads to the conclusion do not reject
H0? (Round your answer to four decimal
places.)
(b) What...

You may need to use the appropriate appendix table or technology
to answer this question.
Consider the following data for two independent random samples
taken from two normal populations.
Sample 1
11
7
13
7
9
7
Sample 2
9
7
8
3
6
9
(a)
Compute the two sample means.
Sample 1Sample 2
(b)
Compute the two sample standard deviations. (Round your answers
to two decimal places.)
Sample 1Sample 2
(c)
What is the point estimate of the difference...

You may need to use the appropriate appendix table or technology to
answer this question.
Studies show that massage therapy has a variety of health benefits
and it is not too expensive. A sample of 11 typical one-hour massage therapy
sessions showed an average charge of $51. The population standard
deviation for a one-hour session is
σ = $7.5.
(a)
What assumptions about the population should we be willing to make
if a margin of error is desired?
We should...

You may need to use the appropriate appendix table or technology
to answer this question.
A newspaper reports that the average expenditure on Valentine's
Day is $100.89. Do male and female consumers differ in the amounts
they spend? The average expenditure in a sample survey of 40 male
consumers was $138.67, and the average expenditure in a sample
survey of 30 female consumers was $61.64. Based on past surveys,
the standard deviation for male consumers is assumed to be $35,...

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